RFC: Refactor CLI into a single program, using argparse

[paulmelnikow]

See #177 (comment).

[paulmelnikow]

There's a lot of repetition here which could be tightened up.

[orta]

Want to leave this with me to wrap up?

[orta]

I took a look into argparse, it has the exact same flaw as commander: no support for the subparsers being optional ( nodeca/argparse#58 nodeca/argparse#99 ) so I threw a few hours last night and this morning at adding it and couldn't get very far ( current WIP is in https://github.com/danger/danger-js/tree/paulmelnikow-refactor-cli )

[paulmelnikow]

Lemme give that a poke. If it comes down to it I'd rather hack on argparse than on commander; the behavior is better documented and the code is in better shape. Worst case, we could wrap a try-catch around the parseArgs bit.

[paulmelnikow]

There's a debug option which does not really debug, but throws an exception when arguments are invalid. Creating a parser to handle the default invocation of danger run and trying that first, then falling back to the hybrid command: this seems to work.

[orta]

OK, so I gave it a look yesterday also and figured it was probably time to take a clean look at all the CLI and ended up in a different place, I simplified Danger's CLI options and added a lot more documentation in #465

Docs: https://github.com/danger/danger-js/pull/465/files#diff-4ac32a78649ca5bdd8e0ba38b7006a1eR11

[paulmelnikow]

Alright, seems like I should close this. Maybe I can jump in some other place.

[peril-staging]

Thanks for the PR @paulmelnikow.

We conform to the Moya Community Continuity Guidelines, which means
that we want to offer any contributor the ability to control their destiny.

So, we've sent you an org invite - thanks 🎉

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[orta]

Peril still gave you invite for helping - that counts to me 👍

Thanks @paulmelnikow - dunno if this would have got fixed had you not started this